The suppression or elimination of EMI/RFI energy has become increasingly important in the past few years. The advent of smaller, more powerful electronic equipment has increased the potential for EMI/RFI interference and its damaging effects.
One area of EMI/RFI shielding that has been largely ignored is the shielding of large or irregular gaps. Such gaps are formed between adjacent structural components such as between a wall of an EMI/RFI enclosure and its shielded door or window frame, between a cable or power supply conduit and an opening in a wall or between a cover and a closure.
Generally, the approach has been to eliminate such gaps altogether by requiring closer tolerances between adjacent parts or redesigning the structures to eliminate the problem. Those gaps which cannot be eliminated have been covered by conductive metal plates or tapes or filled with solid conductive materials, such as conductive caulks and potting compounds.
While the above remedies work to some degree, they are expensive, cumbersome and do not always provide a complete shield. For example, requiring closer tolerances between components reduces the ability to interchange components and adds to the cost of manufacturing. Redesigning of components causes delays and often creates new EMI/RFI problems. Metal plates or tapes are often unsightly and generally do not provide a flexible, maintenance free solution. The existing caulks and potting compounds are expensive to use in that a large volume of material is needed to form a complete EMI/RFI shield, and are generally rigid and inflexible.
The need exists for an easy to apply, inexpensive, conductive material for irregular or large gaps which provides a complete EMI/RFI shield. Additionally, a need exists for such a material that is also flexible and capable of being cured or molded in place at room temperature.